While many kids are hoping to find a Wii U under the Christmas tree on Tuesday, some of the season's most absorbing Nintendo games are available on its other system, the portable 3DS.

"Paper Mario: Sticker Star" ($39.99) takes the cherubic curves of the Mushroom Kingdom and flattens them into an ever-folding papercraft world. Mario himself is a two-dimensional guy in a 3D universe: Turn him sideways and he changes from a full-fledged Goomba stomper to a barely perceptible line on the screen.

The tale begins with Mario's old nemesis, Bowser, crashing the kingdom's comet-watching party and (of course) kidnapping Princess Peach. Bowser's raid scatters the kingdom's sticker collection far and wide, so Mario and his new pal, a "sticker fairy" named Kersti, have to venture out and collect them all.

Mario's main weapons are a mighty hammer and a stiff boot, but different stickers make his attacks more powerful. Most of the battles are fairly easy; you'll need to save the biggest, most damaging stickers for the challenging boss battles. You're also required to collect certain objects and turn them into stickers, which are then used to solve environmental puzzles.

Cleverly designed mazes and an often hilarious script make "Sticker Star," the fourth Paper Mario game, one of the best in the series. Three out of four stars.

"Professor Layton and the Miracle Mask" ($39.99) -- the fifth adventure for the intrepid archaeologist from the Japanese studio Level-5 -- is a mix of family-friendly puzzles and a dark mystery, with a few romantic interludes thrown in for good measure.

Professor Hershel Layton, his young apprentice, Luke, and his assistant, Emmy, are at a carnival in the city of Monte d'Or when a ghostly masked figure attacks, causing a ruckus and turning people to stone. Our heroes run off in pursuit of the Masked Gentleman -- but the story is primarily a framework for several hundred brain-teasers.

Most of these are one-shot logic or observation puzzles, though there's also room in Layton's trunk for a few minigames. One requires you to program a robot around a mice-infested maze; another has you training a rabbit for a job in the circus. You can also connect to the Internet and download a new puzzle every day.

The puzzles are much more amusing than the wordy banter Layton engages in with the folks around Monte d'Or. And one story element -- Emmy's uncomfortable jealousy of Layton's past loves, who reach out to him during the adventure -- feels out of place. But "Professor Layton and the Miracle Mask" has an intriguing plot and enough mental challenges to keep both young and old minds sharp. Three stars.